In many branches of industry there is a need for conductive pigments, with which, for example, plastics, paints, coatings, fibers or similar materials can be produced which are electrically conductive, antistatic or act as a shield against electromagnetic waves. Conductive carbon black is used in large quantities for this purpose, but because of its high light absorption this cannot be used for light or colored coatings.
Additionally, a number of metals and oxide type materials, such as, for example, tin dioxide doped with antimony or indium oxide doped with tin, are also known which can be used as such or used as a coating on other pigments or extenders. Apart from conductivity, only black or gray color shades or metallic effects can be achieved with the majority of known pigments. Some of the known pigments are also not stable to temperature changes or resistant to weathering. EP-A 139,557 also discloses the provision of transparent lamellar substrates, such as for example, mica or glass, with a conductive layer. The pigments obtained in this way are, however, not opacifying and are therefore not suitable for the production of decorative coatings.
There is therefore a need for stable electrically conductive pigments, which are opacifying light or even colored and, apart from conductivity, impart a decorative appearance to the coatings or plastics.